The Dilemma of Genotype Positive-Phenotype Negative Hypertrophic Cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is the most common inherited cardiovascular disease and the leading cause of sudden death in athletes. An autosomal dominant disorder affecting approximately 1 in 500 individuals, HCM has been linked to multiple mutations and exhibits variable phenotypic expression. The utility of cardiovascular screening in diagnosing risk factors for sudden cardiac death continues to be debated intensely. Genetic testing has been employed increasingly in diagnosing HCM, resulting in a subset of patients with genotype positive-phenotype negative disease; these patients carry the mutation for HCM but lack pathologic evidence of disease. These individuals pose a dilemma in the clinical management of HCM: should treatment guidelines for phenotypically normal HCM patients be the same as that of symptomatic patients? Governing bodies continue to disagree, providing conflicting guidelines for sports participation. This review examines the current fund of knowledge regarding HCM and the debate regarding screening.